Line Tracking

After a little digging into my records, I found that nearly 60% of the projects I’ve been involved with over the last three years have used vision and/or line tracking. It seems like integrators and end-users tend to need more help when using these options. If they’re lucky, they may have been trained by an expert somewhere, but they’re often stuck with just a manual (if they’re that lucky) to try and fix some pretty obscure bugs.

I spent last week helping an end-user with their two-robot visual line tracking system. As far as systems like these go, this one’s pretty simple: just two robots, one backlit conveyor, one camera and basically one product. The entire codebase comes in well under a thousand lines. We had issues that were hard to solve despite the simplicity. What follows is my process while debugging several common visual tracking errors.

In part one of this series, we covered gripper design and testing, vision considerations, robot selection, cell layout and choosing the correct number of robots for visual tracking applications. This post will cover some other considerations: conveyor flow, hardware requirements, setup and configuration, and finally, programming.
Here’s the full list with links to each section:
Gripper Vision Robot Selection Layout Number of Robots Relative Conveyor Flow Direction Hardware Setup Programming Relative Conveyor Flow Direction If you consider a simple system with two conveyors: one for parts coming in, and one for parts going out, which direction(s) do they go?

Visual tracking is intimidating, much more intimidating than most other material handling applications. With all the additional hardware required (cameras, encoders, multiplexers) and steps to get things moving (camera calibration, tracking frame calibration, vision process creation, reference setting, accuracy tuning), it’s easy to get overwhelmed. And you haven’t even made any of your other extremely important decisions yet: what robot(s) should I use? What is the best layout for this application?